225 lines
6.4 KiB
C
225 lines
6.4 KiB
C
/* (C) 2017 by sysmocom s.f.m.c. GmbH
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* All Rights Reserved
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*
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* Author: Philipp Maier
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <osmocom/core/logging.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/core/timer.h>
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#include <osmocom/core/fsm.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <openbsc/debug.h>
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#include <openbsc/bsc_msc_data.h>
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#include <openbsc/osmo_bsc_sigtran.h>
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#define RESET_RESEND_INTERVAL 2 /* sec */
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#define RESET_RESEND_TIMER_NO 1234 /* FIXME: dig out the real timer number */
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#define BAD_CONNECTION_THRESOLD 3 /* connection failures */
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enum fsm_states {
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ST_DISC, /* Disconnected from remote end */
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ST_CONN, /* We have a confirmed connection */
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};
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static const struct value_string fsm_state_names[] = {
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{ST_DISC, "ST_DISC (disconnected)"},
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{ST_CONN, "ST_CONN (connected)"},
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{0, NULL},
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};
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enum fsm_evt {
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EV_RESET_ACK, /* got reset acknowlegement from remote end */
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EV_N_DISCONNECT, /* lost a connection */
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EV_N_CONNECT, /* made a successful connection */
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};
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static const struct value_string fsm_evt_names[] = {
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{EV_RESET_ACK, "EV_RESET_ACK"},
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{EV_N_DISCONNECT, "EV_N_DISCONNECT"},
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{EV_N_CONNECT, "EV_N_CONNECT"},
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{0, NULL},
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};
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/* Disconnected state */
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static void fsm_disc_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct a_reset_ctx *reset = (struct a_reset_ctx *)data;
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OSMO_ASSERT(reset);
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LOGP(DMSC, LOGL_NOTICE, "(%s) fsm-state (msc-reset): %s, fsm-event: %s\n", reset->name,
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get_value_string(fsm_state_names, ST_CONN), get_value_string(fsm_evt_names, event));
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reset->conn_loss_counter = 0;
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osmo_fsm_inst_state_chg(fi, ST_CONN, 0, 0);
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}
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/* Connected state */
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static void fsm_conn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct a_reset_ctx *reset = (struct a_reset_ctx *)data;
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OSMO_ASSERT(reset);
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LOGP(DMSC, LOGL_NOTICE, "(%s) fsm-state (msc-reset): %s, fsm-event: %s\n", reset->name,
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get_value_string(fsm_state_names, ST_CONN), get_value_string(fsm_evt_names, event));
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switch (event) {
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case EV_N_DISCONNECT:
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if (reset->conn_loss_counter >= BAD_CONNECTION_THRESOLD) {
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LOGP(DMSC, LOGL_NOTICE, "(%s) SIGTRAN connection down, reconnecting...\n", reset->name);
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osmo_fsm_inst_state_chg(fi, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
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} else
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reset->conn_loss_counter++;
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break;
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case EV_N_CONNECT:
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reset->conn_loss_counter = 0;
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break;
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}
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}
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/* Timer callback to retransmit the reset signal */
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static int fsm_reset_ack_timeout_cb(struct osmo_fsm_inst *fi)
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{
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struct a_reset_ctx *reset = (struct a_reset_ctx *)fi->priv;
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LOGP(DMSC, LOGL_NOTICE, "(%s) reset-ack timeout (T%i) in state %s, resending...\n", reset->name, fi->T,
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get_value_string(fsm_state_names, fi->state));
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reset->cb(reset->priv);
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osmo_fsm_inst_state_chg(fi, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
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return 0;
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}
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static struct osmo_fsm_state fsm_states[] = {
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[ST_DISC] = {
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.in_event_mask = (1 << EV_RESET_ACK),
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.out_state_mask = (1 << ST_DISC) | (1 << ST_CONN),
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.name = "DISC",
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.action = fsm_disc_cb,
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},
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[ST_CONN] = {
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.in_event_mask = (1 << EV_N_DISCONNECT) | (1 << EV_N_CONNECT),
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.out_state_mask = (1 << ST_DISC) | (1 << ST_CONN),
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.name = "CONN",
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.action = fsm_conn_cb,
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},
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};
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/* State machine definition */
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static struct osmo_fsm fsm = {
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.name = "FSM RESET",
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.states = fsm_states,
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.num_states = ARRAY_SIZE(fsm_states),
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.log_subsys = DMSC,
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.timer_cb = fsm_reset_ack_timeout_cb,
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};
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/* Create and start state machine which handles the reset/reset-ack procedure */
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struct a_reset_ctx *a_reset_alloc(const void *ctx, const char *name, void *cb, void *priv)
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{
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OSMO_ASSERT(name);
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struct a_reset_ctx *reset;
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/* Register the fsm description (if not already done) */
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if (osmo_fsm_find_by_name(fsm.name) != &fsm)
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osmo_fsm_register(&fsm);
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/* Allocate and configure a new fsm instance */
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reset = talloc_zero(ctx, struct a_reset_ctx);
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OSMO_ASSERT(reset);
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reset->priv = priv;
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reset->cb = cb;
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strncpy(reset->name, name, sizeof(reset->name));
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reset->conn_loss_counter = 0;
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reset->fsm = osmo_fsm_inst_alloc(&fsm, NULL, NULL, LOGL_DEBUG, "FSM RESET INST");
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OSMO_ASSERT(reset->fsm);
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reset->fsm->priv = reset;
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LOGP(DMSC, LOGL_NOTICE, "(%s) reset handler fsm created.\n", reset->name);
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/* kick off reset-ack sending mechanism */
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osmo_fsm_inst_state_chg(reset->fsm, ST_DISC, RESET_RESEND_INTERVAL, RESET_RESEND_TIMER_NO);
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return reset;
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}
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/* Tear down state machine */
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void a_reset_free(struct a_reset_ctx *reset)
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{
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OSMO_ASSERT(reset);
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OSMO_ASSERT(reset->fsm);
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osmo_fsm_inst_free(reset->fsm);
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reset->fsm = NULL;
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memset(reset, 0, sizeof(*reset));
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talloc_free(reset);
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LOGP(DMSC, LOGL_NOTICE, "(%s) reset handler fsm destroyed.\n", reset->name);
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}
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/* Confirm that we sucessfully received a reset acknowlege message */
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void a_reset_ack_confirm(struct a_reset_ctx *reset)
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{
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OSMO_ASSERT(reset);
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OSMO_ASSERT(reset->fsm);
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osmo_fsm_inst_dispatch(reset->fsm, EV_RESET_ACK, reset);
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}
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/* Report a failed connection */
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void a_reset_conn_fail(struct a_reset_ctx *reset)
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{
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/* If no reset context is supplied, just drop the info */
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if (!reset)
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return;
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OSMO_ASSERT(reset->fsm);
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osmo_fsm_inst_dispatch(reset->fsm, EV_N_DISCONNECT, reset);
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}
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/* Report a successful connection */
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void a_reset_conn_success(struct a_reset_ctx *reset)
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{
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/* If no reset context is supplied, just drop the info */
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if (!reset)
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return;
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OSMO_ASSERT(reset->fsm);
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osmo_fsm_inst_dispatch(reset->fsm, EV_N_CONNECT, reset);
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}
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/* Check if we have a connection to a specified msc */
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bool a_reset_conn_ready(struct a_reset_ctx *reset)
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{
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/* If no reset context is supplied, we assume that
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* the connection can't be ready! */
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if (!reset)
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return false;
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OSMO_ASSERT(reset->fsm);
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if (reset->fsm->state == ST_CONN)
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return true;
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return false;
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}
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